(1) Field of the Invention
The present invention relates generally to automatic watch winders for winding self-winding watches, and in particular to watch winders that end each winding cycle with the orientation of the watch carrier, and the watch supported thereon, at a predetermined number of degrees different from the orientation of the watch carrier at the end of the immediately preceding cycle, thereby imparting to the watch the accuracy and advantages of a tourbillon mechanism.
(2) Description of the Prior Art
The winding mechanism of a self-winding watch is comprised of a bearing mounted pendulum or rotor that is connected through a gear reduction system to the mainspring of the watch. Generally, the rotor can rotate 360° in either direction. However, there are also so-called “hammer” shaped rotors in older self-winding watches that have a limited travel of 150° to 220° rotation. In either case when the watch is worn, the user's random and often rapid arm movements cause the rotor to swing back and forth inertially in both directions around the rotor axis, thereby winding the watch spring. The watch spring generally stores sufficient energy to keep the watch operating 36-48 hours, whether worn or not. Thus, when worn daily, the watch will be sufficiently wound to maintain continuous operation. However, if the watch is not worn regularly, the user must wind the watch, either manually or with a watch winder, or the watch will stop.
Watch winders are typically comprised of an electric drive mechanism that rotates a watch carrier so that the rotor moves relative to the watch spring, thereby effecting winding of the watch. In many watch winders, the watch is supported on a holder with plane of the watch being perpendicular to the axis of rotation. That is, the rotor axis is parallel to the axis of rotation of the drive mechanism, so that the watch rotates in the same plane as the hands of the watch. During the period of activation, the watch is partially or completely rotated several times either in a clockwise or counter-clockwise direction or, alternately, reversing in both directions. The powered rotation of the watch may be controlled to limit the turns per day (TPD) to prevent damage or malfunction due to the forces exerted on the winding mechanism.
One disadvantage of existing watch winders is the inaccuracy imparted to the watch mechanism by the effects of gravity. The effect of gravity on the accuracy of a watch mechanism was first observed in 1795 by Abraham-Louis Breguet. The effect was particularly pronounced in pocketwatches that were carried in the same pocketed position for most of the day, i.e., with the watch being in the same orientation for extended periods of time. Breguet designed a mechanism, known at a “tourbillon” mechanism to counter this effect. In a tourbillon mechanism, the entire escapement assembly including the balance wheel, escapement and pallet fork is mounted for rotation within the watch assembly.
The advent of watches which are worn on the wrist has negated the need for a tourbillon mechanism as an accuracy improver. The random motions of the wrist during the day in effect provide all of the multi-positional needs for averaging out the effect of gravity on the watch's accuracy. Consequently, the modern tourbillon is more an example of fine craftsmanship and an expression of high quality than it is a rate adjustment tool.
However, with the advent of watchwinders, the original positional problem returns. The watchwinder is only active for a short time, e.g., one hour, each day. Consequently, for the remaining time the watch is in a fixed position with the axis of rotation horizontal or slightly tilted, in effect, the same as it would be if it were a pocket watch in the olden days. Thus, there is a need for a watchwinder that negates the effect of gravity, and provides the advantages of a tourbillon mechanism to any watch being wound on the watchwinder.